Articles
PYTHIUM ROOT ROT OF FORCED TULIPS IN VARIOUS SUBSTRATES
To avoid unnecessary waste it is desirable to reuse the substrate.
Experiments were carried out to assess the effect of tulip root remnants in various substrates on infection by Pythium ultimum of roots of forced tulips.
P. ultimum infected root remnants in both riversand and potting soil caused severe root rot.
Storage of these substrates with infected root remnants during six months reduced root rot to a certain extent, but still serious damage occurred.
Autoclaving the substrates before planting resulted in a healthy crop.
Riversand, potting soil and vermiculite containing root remnants from apparently healthy tulips were infested locally to assess the suitability of the root remnants as a food source for P.ultimum and the possible spread of the pathogen during one tulip culture period.
Considerable infection developed after infestation of both non-autoclaved and autoclaved riversand and vermiculite with fresh root remnants.
In potting soil with fresh root remnants damage occurred only after autoclaving the substrate before infestation.
Local infestation of the three substrates with root remnants after they were stored for six months did not result in significant infection.